Special Neural Engineering Seminar: Maria Ironside (Friday Feb. 1st at 1 pm)
Title: Neurocognitive mechanisms of DLPFC tDCS in major depressive disorder
Speaker: Dr. Maria Ironside, Post Doctoral Research Fellow, Center for Depression, Anxiety and Stress Research, McLean Hospital – Harvard Medical School
When: Friday Feb. 1 2019 at 1 pm
Where: CCNY Center for Discovery and Innovation, 4th floor seminar room (CDI 4.352)
Contact: Greg Kronberg (email@example.com, 212-650-8876) for access to CDI building
The difficulty in treating mood and anxiety disorders has sparked clinical interest in novel treatments, such as transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC). However, underlying mechanisms of action are unclear. It is established that people with mood and anxiety disorders have negative cognitive biases, such as increased vigilance to threat. Psychiatric treatments have acute effects on these cognitive biases which predict later therapeutic action. Such effects are proposed as cognitive biomarkers of response.
A healthy volunteer investigation revealed an anxiolytic like effect (reduced threat vigilance) of a single session of tDCS on a behavioural test of proven clinical relevance (Ironside et al., 2016, Biological Psychiatry). Complementing these data, we used functional imaging to reveal that, in a sample of trait anxious females, tDCS of the DLPFC increased activation in an attentional control network and reduced amygdala response to fearful face distractors (Ironside et al., 2018, JAMA Psychiatry). This provides causal evidence that modulating activity in the DLPFC inhibits amygdala response to threat, providing a potential neural mechanism for the previous reduction in vigilance to threat. Collectively, these results propose an emerging neurocognitive model for the mechanisms of action of tDCS. We also examined pairing tDCS with attentional bias modification training and found no effect of stimulation.
Together, findings point to an anxiolytic-like effect of DLPFC tDCS on cognitive and neural biomarkers relevant to mood and anxiety disorders, indicating potential cognitive and underlying neural mechanisms that may mediate the reported clinical efficacy of DLPFC tDCS. This has implications as the identification of treatment response markers could aid patient selection for future trials and ultimately treatment selection for patients.